In-vivo measuring systems are known in the art. Some autonomous capsule like in-vivo devices, which are swallowed and traverse the gastrointestinal (GI) system, may include an imaging sensor, or imager, for imaging (e.g., capturing images or taking pictures of) the interior of the GI system. An in-vivo device may include one or more imagers and/or one or more sensors of other types (e.g., pH sensor, pressure sensor, temperature sensor, etc.), and/or various types of tools (e.g., micro electro-mechanical system, or “MEMS”), for example to perform surgical operations in vivo and/or to administer medication in the GI system, for example from a container contained in an in-vivo device. While in operation (e.g., after swallowing), an in-vivo device may wirelessly exchange data with an external receiver. For example, the in-vivo device may wirelessly transmit data (e.g., sensory data; e.g., image data pertaining to captured images) to the external receiver, and the external receiver may wirelessly transmit instructions back to the in-vivo device, for example instructions that may depend on data transmitted from the in-vivo device. For example, the in-vivo device may transmit image frames to the receiver, and the receiver may transmit an instruction to the in-vivo device, for example, to change the image frame capturing rate, for example, based on captured images. (An image frame is a data block/set that may include image data (and/or other sensory data), metadata, synchronization data, etc.)
In many cases, it may be important to associate a captured image or a sensor's measurement with the location in the GI tract at which the image (or measurement) was taken, or a physiological parameter (e.g., pH, pressure, etc.) was sensed in order to interpret the image or measurement properly. For example, a pH value equal to, say, 6.3 may be regarded as normal if it is measured in one GI portion and abnormal if it is measured in another portion of the GI tract.
Magnetic based localization systems enable localization of in-vivo devices in the GI tract. Typically, a magnetic localization system is external to the subject, stationary and robust. A magnetic based localization system typically includes one or more magnetic field sources to generate magnetic fields in order for them to be sensed in/by the in-vivo device whose location is sought. Since conventional localization systems are stationary, freedom of movement of the subject swallowing the in-vivo device is very limited.